The present invention relates to a digital video and audio signal recording and reproducing apparatus, and, in particular, to control data associated with digital audio signals.
Broadcasting of stereo programs and bilingual programs or multilingual programs such as the Euro Sports channel has occurred for many years, and the number of such broadcasts is expected to increase.
In the present broadcasting system, only stereo programs and bilingual (main language and sub language) programs can be distinguished. An example of a bilingual broadcast is a program in which the main language is Japanese and the sub language is English. Another example of a bilingual broadcast is a sports program in which the main xe2x80x9clanguagexe2x80x9d is a commentary and the sub xe2x80x9clanguagexe2x80x9d is a commentary about a team. As used herein and in the claims, xe2x80x9cmultilingualxe2x80x9d encompasses both of the aforementioned examples, namely, audio signals with the same content in different languages and audio signals with different contents in the same language.
In a commercial digital video cassette recorder (VCR) format that has been partially disclosed, recording and reproducing formats of digital audio signals have been defined for both High Definition (HD) video and Standard Definition (SD) video. For SD signals, a two-channel mode (SD 2 ch) and a four-channel mode (SD 4 ch) have been defined. For HD signals, a four-channel mode (HD 4 ch) and an eight-channel mode (HD 8 ch) have been defined. These four modes are considered in two groups. The amount of data used to represent a SD or HD signal in the first of the modes is twice the amount of data used to represent the signal in the second of the modes.
The first group, in which 16-bit linear quantizing is performed at sampling frequencies of 48 kHz, 44.1 kHz, and 32 kHz, includes the two-channel mode of SD and the four-channel mode of HD, shown in FIGS. 1A and 1C, respectively.
The second group, in which 12-bit non-linear quantizing is performed at a sampling frequency of 32 kHz, includes the four-channel mode of SD and the eight-channel mode of HD, shown in FIGS. 1B and 1D, respectively.
Ten tracks are used to represent one SD video frame according to the NTSC standard (525 lines/60 Hz). Twelve tracks are used to represent one SD video frame according to the PAL standard (525 lines/50 Hz). In ten tracks (60 Hz SD system) or twelve tracks (50 Hz SD system), there is also capacity for two channels of digital audio signals each in 16-bit mode or four channels in 12-bit mode.
Twenty tracks (1125 lines/60 Hz) or twenty four tracks (1250 lines/50 Hz) are used to represent one HD video frame.
Thus, when an HD signal is recorded, in the 16-bit mode, audio signals for four channels can be recorded, and, in the 12-bit mode, audio signals for eight channels can be recorded.
A control data area AAUX for recording control data associated with the digital audio data is provided in each track. To identify the allocation of audio data on a plurality of channels (audio data stored on each channel), a mode signal referred to as AUDIO MODE is recorded in the AAUX area. FIG. 2 is a table indicating the meaning of the values of the AUDIO MODE data, using the following abbreviations:
CHN: The number of audio channels represented in a group of five tracks, that is, whether the audio signal is recorded using 16 bits or 12 bits.
L: Left channel of stereo signal
R: Right channel of stereo signal
M, M1, M2: Monaural signals
C: Center channel of three-channel stereo (3/0 stereo) or four-channel stereo (3/1 stereo)
S: Surround channel of 4-channel stereo (3/1 stereo)
LS: Left surround channel of 4-channel stereo (2/2 stereo)
RS: Right surround channel of 4-channel stereo (2/2 stereo) ?: Indistinguishable xe2x88x92: No information
AUDIO MODE data is recorded in every track. The same AUDIO MODE data is redundantly recorded in each of the tracks in a channel.
When a bilingual broadcast TV program is recorded in an SD two-channel record mode in which the number of quantizing bits is 16 and the sampling frequency is 48 kHz, as shown in FIG. 3, monaural signals are recorded on CH1 and CH2. The AUDIO MODE of both channels, each comprising five tracks, is (0010). In FIG. 3, each square indicated by solid line represents audio data of five tracks. However, from the AUDIO MODE signals thus recorded, it cannot be determined whether the audio signals are a bilingual.
As shown in FIG. 4, at least three possibilities exist when the AUDIO MODE is recorded as shown in FIG. 3. The first possibility is that Japanese language is recorded on channel 1 and English language is recorded on channel 2. The second possibility is that general commentary is recorded on channel 1 and the specific commentary, such as for a team, is recorded on channel 2. The third possibility is that acting dialogue is recorded on channel 1 and background music is recorded on channel 2.
A similar inability to distinguish whether the audio signals recorded in the available channels are related exists in the four channel mode of SD, the four channel mode of HD and the eight channel mode of HD.
When Japanese stereo sounds and English stereo sounds have been recorded on a tape in a four-channel mode, until they are reproduced, the recorded sounds cannot be distinguished. A VCR that can record audio signals on eight channels, such as a HDVCR, can record a four-language stereo broadcasting program simultaneously with the above-mentioned Euro Sports channel. However, in this case, likewise, such a recording format cannot be distinguished.
Therefore, an object of the present invention is to provide a digital audio recording and reproducing system which avoids the aforementioned disadvantages of the prior art.
Another object of the present invention is to provide a digital audio signal recording and reproducing apparatus that can easily determine whether digital audio signals on a plurality channels represent audio signals with different contents or multilingual audio signals that have related contents.
In accordance with an aspect of this invention, the foregoing objects are met by provision of a method of and a system for generating data, in which a digital audio signal including a plurality of audio channels is received. A multilingual indication is generated when at least two of the audio channels are associated with a common program, and the multilingual indication is combined with the digital audio signal.
In accordance with another aspect of this invention, there are provided a method of and a system for reproducing data, in which a digital audio signal including a plurality of audio channels and a multilingual indication indicating whether at least two of the audio channels are associated with a common program is received. A display is activated when the multilingual indication indicates that at least two of the audio channels are associated with a common program.
According to the present invention, a recorded multilingual program can be recognized without need to reproduce all channels thereof. A main audio signal can be automatically reproduced without need to select a channel. Additionally, when multilingual channels are recorded, one of the languages can be selected by a user.
The above, and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the present invention when read in conjunction with the accompanying drawings in which corresponding parts are identified by the same reference numeral.